“Seaweed-based blue food systems in China: environmental performance, metabolic dynamics, and trade-mediated sustainability transitions”
Xiu Gao began her doctoral studies back in 2023 at Shanghai Jiao Tong University (SJTU) in China. During her time there, she spent, among other things, a hundred days aboard several research vessels in the Pacific Ocean, the South China Sea, and the Philippine Sea. Her work at SJTU primarily involved the analysis of water samples to assess phytoplankton physiological status and nutrient concentrations, including phosphorus and nitrogen. She conducted field experiments to investigate the effects of different types and concentrations of heavy metal ions on phytoplankton growth and chlorophyll fluorescence. She also performed extensive laboratory analyses using microscopes, nutrient analyzers, pulse-amplitude-modulated fluorometry (PAM), spectrophotometers, and other analytical instruments.
Since December 2025, Xiu Gao has been a joint doctoral student at KTH as part of a collaboration between the two universities. Her work continues to have a strong marine focus, but now with an emphasis on macroalgae, or seaweed. Among other things, she is analyzing phosphorus flows in China’s seaweed industry over several decades using material flow analysis, quantifying the phosphorus absorbed from the ocean during production and examining how consumption patterns drives downstream phosphorus flow. The goal is to identify key phosphorus hotspots and support the sustainable development of the seaweed industry
Xiu Gao is collaborating with Vita Weitong Xu, another doctoral student affiliated with the Blue Food centre and the KTH–SJTU joint PhD program, on a life cycle assessment of China’s seaweed industry in Fujian province, one of the major seaweed-producing regions in China.
Looking ahead, Xiu Gao plans to further develop her skills in various tools used in industrial ecology and apply them to the Chinese context, given that China is the world’s largest producer of seaweed and one of the largest seaweed consumption markets. She aims to more accurately quantify and understand the environmental issues associated with seaweed production and to support the sustainable production and consumption of seaweed.
Xiu Gao’s project is particularly relevant to Blue Food’s research areas 1: Sustainability and resilience and 4: Primary production – aquaculture
Supervisors
- Fredrik Gröndahl, KTH
- Jiechen Wu, KTH
- Jean-Baptiste Thomas, KTH
- Ji Li, Shanghai Jiao Tong University